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Home -> Community -> Mailing Lists -> Oracle-L -> RE: is null / = null query
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This is the correct answer, because NULL is never EQUAL to NULL. There are
a few exceptions (NVL, DECODE) but
the classic defition of NULL is "unknown value", therefore you can't
determine it's value at all.
I know this is theory gook, but it's the reasoning behind what you saw.
HTH
Lisa Rutland Koivu
Oracle Database Administrator
Qode.com
4850 North State Road 7
Suite G104
Fort Lauderdale, FL 33319
V: 954.484.3191, x174 F: 954.484.2933 C: 954.658.5849
"The information contained herein does not express the opinion or position of Qode.com and cannot be attributed to or made binding upon Qode.com."
-----Original Message-----
From: GKor_at_rdw.nl [mailto:GKor_at_rdw.nl]
Sent: Thursday, November 09, 2000 9:16 AM
To: Multiple recipients of list ORACLE-L
Subject: is null / = null query
Hi everyone
I have launched the following query in SQL*PLUS
SQL> L
1* SELECT COUNT(*) FROM WERK_ORDER WHERE RESULT_CODE_WO = NULL;
SQL> /
0
1 row selected.
SQL> SELECT COUNT(*) FROM WERK_ORDER WHERE RESULT_CODE_WO IS NULL; 301
1 row selected.
SQL> i did'nt expect to get answer on the first query
anyone with an explanation or is this a undocumented feature ?
thanks
gkor_at_rdw.nl
rdw the netherlands
-- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: INET: GKor_at_rdw.nl Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). ------_=_NextPart_001_01C04A5C.93FE051E Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printableReceived on Thu Nov 09 2000 - 08:51:44 CST
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<TITLE>RE: is null / =3D null query</TITLE>
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<P><FONT SIZE=3D2>This is the correct answer, because NULL is never =
EQUAL to NULL. There are a few exceptions (NVL, DECODE) but =
</FONT>
<BR><FONT SIZE=3D2>the classic defition of NULL is "unknown =
value", therefore you can't determine it's value at all.</FONT>
</P>
<P><FONT SIZE=3D2>I know this is theory gook, but it's the reasoning =
behind what you saw. </FONT>
</P>
<P><FONT SIZE=3D2>HTH</FONT>
</P>
<P><FONT SIZE=3D2>Lisa Rutland Koivu</FONT>
<BR><FONT SIZE=3D2>Oracle Database Administrator</FONT>
<BR><FONT SIZE=3D2>Qode.com</FONT>
<BR><FONT SIZE=3D2>4850 North State Road 7</FONT>
<BR><FONT SIZE=3D2>Suite G104</FONT>
<BR><FONT SIZE=3D2>Fort Lauderdale, FL 33319</FONT>
</P>
<P><FONT SIZE=3D2>V: 954.484.3191, x174</FONT>
<BR><FONT SIZE=3D2>F: 954.484.2933 </FONT>
<BR><FONT SIZE=3D2>C: 954.658.5849</FONT>
<BR><FONT SIZE=3D2><A HREF=3D"http://www.qode.com" =
TARGET=3D"_blank">http://www.qode.com</A></FONT>
</P>
<P><FONT SIZE=3D2>"The information contained herein does not =
express the opinion or position of Qode.com and cannot be attributed to = or made binding upon Qode.com."</FONT></P>
<BR>
<P><FONT SIZE=3D2>-----Original Message-----</FONT>
<BR><FONT SIZE=3D2>From: GKor_at_rdw.nl [<A =
HREF=3D"mailto:GKor_at_rdw.nl">mailto:GKor_at_rdw.nl</A>]</FONT>
<BR><FONT SIZE=3D2>Sent: Thursday, November 09, 2000 9:16 AM</FONT>
<BR><FONT SIZE=3D2>To: Multiple recipients of list ORACLE-L</FONT>
<BR><FONT SIZE=3D2>Subject: is null / =3D null query</FONT>
</P>
<BR>
<BR>
<BR>
<P><FONT SIZE=3D2>Hi everyone</FONT>
</P>
<P><FONT SIZE=3D2>I have launched the following query in =
SQL*PLUS</FONT>
</P>
<P><FONT SIZE=3D2>SQL> L</FONT>
<BR><FONT SIZE=3D2> 1* SELECT COUNT(*) FROM WERK_ORDER WHERE =
RESULT_CODE_WO =3D NULL;</FONT>
<BR><FONT SIZE=3D2>SQL> /</FONT>
<BR><FONT SIZE=3D2> =
0</FONT>
</P>
<P><FONT SIZE=3D2>1 row selected.</FONT>
</P>
<P><FONT SIZE=3D2>SQL> SELECT COUNT(*) FROM WERK_ORDER WHERE =
RESULT_CODE_WO IS NULL;</FONT>
<BR><FONT SIZE=3D2> 301</FONT>
</P>
<P><FONT SIZE=3D2>1 row selected.</FONT>
</P>
<P><FONT SIZE=3D2>SQL></FONT>
</P>
<P><FONT SIZE=3D2>i did'nt expect to get answer on the first =
query</FONT>
</P>
<P><FONT SIZE=3D2>anyone with an explanation or is this a undocumented =
feature ?</FONT>
</P>
<P><FONT SIZE=3D2>thanks</FONT>
</P>
<P><FONT SIZE=3D2>gkor_at_rdw.nl</FONT>
<BR><FONT SIZE=3D2>rdw the netherlands </FONT>
<BR><FONT SIZE=3D2>-- </FONT>
<BR><FONT SIZE=3D2>Please see the official ORACLE-L FAQ: <A =
HREF=3D"http://www.orafaq.com" = TARGET=3D"_blank">http://www.orafaq.com</A></FONT>
<BR><FONT SIZE=3D2>-- </FONT>
<BR><FONT SIZE=3D2>Author: </FONT>
<BR><FONT SIZE=3D2> INET: GKor_at_rdw.nl</FONT>
</P>
<P><FONT SIZE=3D2>Fat City Network Services -- (858) =
538-5051 FAX: (858) 538-5051</FONT>
<BR><FONT SIZE=3D2>San Diego, =
California -- Public Internet = access / Mailing Lists</FONT>
<BR><FONT =
SIZE=3D2>---------------------------------------------------------------= -----</FONT>
<BR><FONT SIZE=3D2>To REMOVE yourself from this mailing list, send an =
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<BR><FONT SIZE=3D2>the message BODY, include a line containing: UNSUB =
ORACLE-L</FONT>
<BR><FONT SIZE=3D2>(or the name of mailing list you want to be removed =
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